<?php

if (!defined('BASEPATH'))
    exit('No direct script access allowed');
/*
 * This is a PHP library that handles calling reCAPTCHA.
 *    - Documentation and latest version
 *          http://recaptcha.net/plugins/php/
 *    - Get a reCAPTCHA API Key
 *          http://recaptcha.net/api/getkey
 *    - Discussion group
 *          http://groups.google.com/group/recaptcha
 *
 * Copyright (c) 2007 reCAPTCHA -- http://recaptcha.net
 * AUTHORS:
 *   Mike Crawford
 *   Ben Maurer
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

/**
 * Recaptcha modified to integrate easily with Code Igniter
 *
 * @package     CodeIgniter
 * @subpackage  Libraries
 * @category    Captcha
 * @author      Jon Trelfa <jtrelfa@gmail.com>
 */
class Recaptcha {

    var $_rConfig;
    var $_CI;
    var $_error;

    function __construct() {
        $this->_CI = & get_instance();
        $this->_CI->config->load('recaptcha');
        $this->_CI->lang->load('recaptcha');

        $this->_rConfig = $this->_CI->config->item('recaptcha');

        log_message('info', $this->_CI->lang->line('recaptcha_class_initialized'));
    }

    /**
     * Calls an HTTP POST function to verify if the user's guess was correct
     * @param string $privkey
     * @param string $remoteip
     * @param string $challenge
     * @param string $response
     * @param array $extra_params an array of extra variables to post to the server
     * @return ReCaptchaResponse
     */
    function check_answer($remoteip, $challenge, $response, $extra_params = array()) {
        log_message('debug', 'Recaptcha::check_answer(' . $remoteip . ',' . $challenge . ',' . $response . ',' . print_r($extra_params, TRUE) . ')');
        if ($this->_rConfig['private'] == '') {
            log_message('error', $this->_CI->lang->line('recaptcha_no_private_key'));
            return FALSE;
        }

        if ($remoteip == null || $remoteip == '') {
            log_message('error', $this->_CI->lang->line('recaptcha_no_remoteip'));
            return FALSE;
        }

        //discard spam submissions
        if ($challenge == null || strlen($challenge) == 0 || $response == null || strlen($response) == 0) {
            $this->_error = 'incorrect-captcha-sol';
            return FALSE;
        }

        $response = $this->_http_post(
                $this->_rConfig['RECAPTCHA_VERIFY_SERVER'], "/verify", array(
            'privatekey' => $this->_rConfig['private'],
            'remoteip' => $remoteip,
            'challenge' => $challenge,
            'response' => $response
                ) + $extra_params
        );
        log_message('debug', 'Recaptcha::_http_post response:' . print_r($response, TRUE));
        $answers = explode("\n", $response[1]);

        if (trim($answers[0]) == 'true') {
            return TRUE;
        } else {
            $this->_error = $answers[1];
            return FALSE;
        }
    }

    /**
     * Gets the challenge HTML (javascript and non-javascript version).
     * This is called from the browser, and the resulting reCAPTCHA HTML widget
     * is embedded within the HTML form it was called from.
     * @param string $pubkey A public key for reCAPTCHA
     * @param string $error The error given by reCAPTCHA (optional, default is null)
     * @param boolean $use_ssl Should the request be made over ssl? (optional, default is false)

     * @return string - The HTML to be embedded in the user's form.
     */
    function get_html($uri, $lang = 'en', $use_ssl = false) {
        log_message('debug', 'Recaptcha::get_html(' . $use_ssl . ')');
        if ($this->_rConfig['public'] == '') {
            log_message('error', $this->_CI->lang->line('recaptcha_no_private_key'));
            return $this->_CI->lang->line('recaptcha_html_error');
        }

        if ($use_ssl) {
            $server = $this->_rConfig['RECAPTCHA_API_SECURE_SERVER'];
        } else {
            $server = $this->_rConfig['RECAPTCHA_API_SERVER'];
        }

        $errorpart = '';
        if ($this->_error !== '') {
            $errorpart = "&amp;error=" . $this->_error;
        }
        $html_data = array(
            'server' => $server,
            'key' => $this->_rConfig['public'],
            'theme' => $this->_rConfig['theme'],
            'lang' => $lang,
            //appends The error display for the reCaptcha to the url
            'errorpart' => $errorpart
        );
        //load a view - more configurable than embedding HTML in the library
        return $this->_CI->load->view($uri, $html_data, TRUE);
    }

    /**
     * gets a URL where the user can sign up for reCAPTCHA. If your application
     * has a configuration page where you enter a key, you should provide a link
     * using this function.
     * @param string $domain The domain where the page is hosted
     * @param string $appname The name of your application
     */
    function get_signup_url($domain = null, $appname = null) {
        return "http://recaptcha.net/api/getkey?" . $this->_qsencode(array('domain' => $domain, 'app' => $appname));
    }

    /**
     * Encodes the given data into a query string format
     * @param $data - array of string elements to be encoded
     * @return string - encoded request
     */
    function _qsencode($data) {
        log_message('debug', "Recaptcha::_qsencode(\n" . print_r($data, TRUE) . "\n)");
        //http_build_query() = PHP 5 ONLY!
        return http_build_query($data);
    }

    /**
     * Submits an HTTP POST to a reCAPTCHA server
     * @param string $host
     * @param string $path
     * @param array $data
     * @param int port
     * @return array response
     */
    function _http_post($host, $path, $data, $port = 80) {
        log_message('debug', 'Recaptcha::http_post(' . $host . ',' . $path . ',' . print_r($data, TRUE) . ',' . $port . ')');

        $req = $this->_qsencode($data);
        $http_request = implode('', array(
            "POST $path HTTP/1.0\r\n",
            "Host: $host\r\n",
            "Content-Type: application/x-www-form-urlencoded;\r\n",
            "Content-Length:" . strlen($req) . "\r\n",
            "User-Agent: reCAPTCHA/PHP\r\n",
            "\r\n",
            $req));
        $response = '';
        if (false == ( $fs = @fsockopen($host, $port, $errno, $errstr, 10) )) {
            log_message('error', $this->_CI->lang->line('recaptcha_socket_fail'));
        }

        fwrite($fs, $http_request);
        while (!feof($fs)) {
            $response .= fgets($fs, 1160); // One TCP-IP packet
        }
        fclose($fs);
        $response = explode("\r\n\r\n", $response, 2);

        return $response;
    }

}
